Railway switch lock



y 1, 1958 E. J. KROMHOLZ 2,

RAILWAY SWITCH LOCK 2 Sheets-Sheet 1 Filed May 6, 1954 i e/ward ffl romholz Q Z a? July 1, 1958 E. J. KROMHOLZ RAILWAY SWITCH LOCK 2 Sheets-Sheet 2 Filed May 6, 1954 Edward J MOMAOZZ United States Pate RAILWAY SWITCH LOCK Edward J. Kromholz, Rockford, Ill.

Application May 6, 1954-, Serial No. 427,993

10 Claims. (Cl. 246-=16l)) This invention relates to automatic safety switch locking mechanisms for spring or hand-thrown switches on railroads, and is more particularly concerned with improvements upon the mechanism disclosed in my Patent 2,546,454, issued March 27, 1951.

in the mechanism disclosed in said prior patent, dogs are engageable in either of two sets of notches provided in a keeper bar reciprocable with the switch throw-bar to lock the switch points positively in either open or closed .position, the dogs being pivotally mounted on a stationary support relative to which the keeper bar is guided for sliding movement and there being a yoke for actuating the dogs reciprocable relativeto. the dogs, spring-pressed to a retracted position andoperable magnetically in the other direction. In accordance with the present invention, spring-pressed plungers are provided working between the dogs andthe throw-bar and arranged to move past a dead-center position inthe movement of the throw bar one Way or the other, whereby to exert spring pres-- sure on the throw-bar tendingto move it all the way to whichever extreme position it is approaching. In that way the switch points are. definitely in either the fully open position or the fully closed position and are never apt to be left in an in-between position and cause a serious wreck or at leastserious damage to the switch.

The invention is illustratedin the accompanying drawin gs, in which Fig. 1 is a planview of a spring switch installation embodying my improved magnetically operate locking mechanism;

Fig. 2 is anenlargementof a portion of Fig. l;

Fig. 3 is a view partly in side elevation and partly in section on line 3--3 of. Fig. 2 showing the yoke in retracted position with the power-oil lock engaged;

Fig. 4 is an electric circuit diagram applicable to Figs. l to 3;

Fig. 5 is a view similar to Fig. 2 but on a larger scale and omitting the power-off lock, and

Fig. 6 is a fragmentary view along the lines of Fig. 5 but showing the throw-bar keeper bar locked in its other extreme position.

The samev reference numerals are applied to corresponding parts throughout these views.

Referring to the drawings, the reference numerals 8 and 9 designate. the conventional points for the spring switch illustrated, which are movable to the right with reference to the main track rails 10 and 11 against resistance of a spring Sin the cylinder 12", as, for example, when a locomotive comes outof a siding onto the main track. The cylinder 12 is connected to one end of the usual throw-bar 13 which inturn is pivotally connected with the points 8 and 9 sothatthese points move together from one extreme position to the other. The usual piston I parts Pworking in the cylinder 12 in cooperation with the aforesaidspring have a-piston rod 14 extending therefrom from the cylinder tothe arm. llS'attached to the lower end Fatentod July 1, 1958 be turned in the usual way by means of a lever when the latter is swung upwardly from its lower locked position to the usual horizontal operating position. With this conventional arrangement it is clear that the points 8 and 9 will be moved back and forth with the throw-bar 13 as many times as there are passing carriages Whenever a locomotive with or without some cars attached comes out the siding onto the main track, thus accounting for all of the clatter and needless wear and tear on all of the equipment involved, and it is easy to understand that such operation results in excessive wear on the relatively slender points and that they are, therefore, apt to break and cause a serious wreck, or the wear on the points may be responsible for the switch not being closed tightly enough, thus giving rise to the possibility of a wreck due to the switch being accidentally opened farther.

As disclosed in my Patent 2,546,454, the two ties 20, onto one end of which the base 21 of the switch stand is bolted and which extend under the rails 10 and 11 and have these rails fastened thereto, indicated, are extended on the other side of the track, as indicated at 22, to support the magnetic locking mechanism 23. The throw-bar i3 is laterally adjustably connected by means of a bolt 2 with the end of a keeper bar 25 forming, in eifect, a direct extension of the throw-bar. This keeper bar has two sets of keepers in the form of V-notches 26 and 27 provided therein to cooperate wedgingly with the V-shaped teeth on the free ends of dogs or latch memhers 29 disposed on opposite sides of the bar 25 and pivotally mounted at their remote ends, as at 30, on a crosspiece 3i. The cross-piece 31 is preferably a metal strap bolted at its ends 32 to the ties 2i] and having its intermediate portion 33 forming a depressed support for the pivoted ends of the dogs 29. The dogs or latch members 29 are shown in released or retracted position in Figs. 2 and 5, but it will be understood that they engage in notches 26 when holding the switch points 8 and 9 in open position, and that they engage in notches 27 when holding these points in closed position. A yoke 34 is reciprocable with the armature 35 of the electromagnetic coil 36 to actuate the dogs 29 instantly whenever this electromagnetic coil is energized. This yoke 34 is slidably supported on the pivoted ends of the dogs 29 and carries a pair of rollers 37 mounted on the rivets 38 for anti-friction rolling contact on the backs of the dogs 29, so as to move the dogs inwardly for tight locking engagement in the notches 26, or 2.7, as the case may be, when the yoke 34 has been moved forward enough to run the rollers 3"] to the toothed free ends of the dogs. The V shape of the teeth 28 gives a wedging action to insure complete opening movement and complete closing movement of the switch points, because if the notches are not in good register with the teeth on the dogs, the dogs will force the switch points to move the necessary amount when the dogs are pressed home. Assuming now that the energization of the controlling electromagnetic coil 36 is maintained so long as the train for whose safe travel relative to the switch points the locking dogs have been actuated, it should be clear that the danger of any accidents due to farther opening of the switch is positively eliminated, also that when the switch points 3 and 9 are moved to the right by the pilot wheels of the locomotive coming out of the siding the circuit for the electromagnetic coil 36 is closed and kept closed thereafter until the locomotive and the car or cars thereto attached have all been run onto the main track to a distance of say thirty feet from the switch, thereby eliminating not only the clatter and wear incident to numerous back and forth movements of the switch points, but also the hazards which such wear is responsible for, there being also avoided the possibility of the condition arising that has frequently caused a lot of damage railway equipment, namely, where the switch points close under spring pressure when part of a train or one end of a car thereof is still on the siding unknown to theengineer when he stops the forward travel of the engine too soon and starts backing up. The yoke 34 in moving to its locking position moves over the pivoted ends of the dogs toward the toothed portions and, therefore, holds the dogs positively in locked position. The yoke 3 has an upwardly bent rear flange 39 that is adjustahly connected by bolts 4% with ears ill on the ends of a cross-piece provided on the end of the armature 35, whereby to transmit movement from the armature 35 to the yoke 34 and permit accurately predetermining the forward limit position of the yoke 34 with respect to the dogs 29 by proper adjustment of the bolts it) in reference to the throw of the armature 35. A rod 43 (Fig. 1) extends rearwardly from the armature 35 through a hole in the cross portion or" a U-shaped yoke 44 that is rigidly connected to the frame of the electromagnet, and a wing nut 45 is threaded adjustably on the outer end of the rod 43 to compress a coiled compression spring 46 to the desired extent, this spring being coiled around the rod 43 between the cross-portion of the yoke id and the nut 45. In that way, the armature 35 is assured of immediate return to retracted position the instant the electromagnetic coil 35 is deenergized, and the yoke 34 is accordingly returned to retracted position, releasing the dogs 29. The mechanism 23 is carried on straps bolted to the tics 20, the intermediate portions of these straps being depressed similarly as the intermediate portion 33 of the strap 31, for a similar reason. A switch point circuit control switch 59 has its crank 51 pivotally connected by a link 52 with the adjacent switch point 8, as shown in Fig. 1 to close the circuit through coil 36 automatically whenever the points 8 and 9 are shifted to open position, whether by hand or by a locomotive or train coming out of the siding.

The operation of the locking mechanism is diagrammatically illustrated in Fig. 4 in which 53 and 54 are the track relays, 55 the time release relay, and St} the switch point circuit control switch. The conventional track batteries are indicated at B1 and B: and the usual insulated joints are indicated at 56 for the main tracks and lit, and at 57 are indicated similar joints for the tracks 58 in the siding. 59 designates the key release between the line 60 and the coil 36 of the magnetic locking mechanism 23.

Assuming the key release 59 is in the closed circuit position shown and that a locomotive, with or without cars attached, one of whose trucks is indicated at T, has run from the siding onto the main track, relay 53 is closed, as shown, and the electromagnetic coil 36 is accordingly energized, freezing the switch points 8 and 9 in the open position, and they remain so until the locomotive and the car or cars attached have passed the joints 56 located a distance of say thirty feet from the switch 3-9. A

switchman, after locking the hand lover of switch stand 17 (Fig. 1) may also open the switch by lever and thereby cause relay 53 to close and freeze the points 8-9 in open position. After the train has passed joints 56, going away from the switch, relay 53 opens and relay 54 closes but only after the time release 55 has permitted the electromagnetic coil 36 to deenergize long enough to release the dogs 29 and let the switch 39 close. Hence, regardless of what the engineer may do, he cannot run afoul of the switch, because if he starts backing up before his train has passed the joints 56 the switch is certain to be locked open and no damage to any railway equipment could therefore result, and, on the other hand, if he starts backing up after his train has passed the joints 56 the switch is certain to be closed. There is no possibility of having the switch closed with part of the train on the main track and the rest on the siding or one end of a caron the main track and the other end on the other track. It is also clear that a train approaching the switch 8-9 on the main track running against the points will by its weight and the shunting of the tracks, in the manner 4 common to block signal operation, cause relay 54 to close and thereby freeze the points 89 in closed position.

In accordance with the present invention, the dogs 29, as more clearly appears in Figs. 2, 5 and 6, have springpressed plungers 61 working between the dogs 29 and the keeper bar or throw-bar extension 25 and arranged to move past a dead-center position in the movement of the throw-bar 13 in either direction, whereby to exert heavy enough spring pressure on the throw-bar to assure its moving all the way to whichever extreme position it is approaching, namely, fully open switch or fully closed switch position, instead of being apt to be left in an inbetween position which might cause a serious wreck or at least serious damage to the switch. The plungers 61 have hinge connections with the bar 25, as indicated at 62, and are reciprocable in holes 63 provided in crossheads 64 pivotally mounted in bearings 65 in the dogs 29. The dogs are longitudinally recessed, as indicated at 66, to provide working space for the projecting ends of the plungers 61. Coiled compression springs 67 are preloaded and caged between the hinged ends of the p-lungers 61 and the cross-heads 64 and they provide a suflicient component in the endwise direction of the bar 25 to close the switch under appreciable pressure or hold it open under similar pressure. Fig. 5 shows the open position and Fig. 6 the closed position, the dogs 29 being shown retracted in Fig. 5 but being shown in the operative position in Fig. 6. It is evident from Fig. 6 that in the locking engagement of the dogs 29 in notches 26 or 27 in bar 25 the springs 67 are further compressed. Hence, if, despite the spring pressure of the springs 67, the bar 25, due to unusual friction resisting its movement or due to an accumulation of dirt around the switch points 8 and 9 interfering with freedom of operation, is not moved all the way to the fully open switch or fully closed switch position before the dogs 29 are thrown to locked position, the energization of the electro-magnetic coil 36 to lock said dogs is made to help the switch movement two ways: namely, by the further loading of springs 67, as indicated in Fig. 6, and by the wedging engagement of the teeth 28 in the notches 26 or 27.

The present improved locking mechanism which by virtue of the over-center action of plunger 61 is assured of full movement makes it practical to provide a poweroff lock for positively locking the throw-bar 13 by means of the keeper bar 25 in whichever extreme position it happens to be at the time of power failure in the line circuit 60. The power-off lock is indicated at 68 in y Figs. 1 to 4 and is omitted in Figs. 5 and 6, because it should be evident from the foregoing description that the switch lock is entirely practical without it, but in certain installations where the additional safety precaution makes a power-off lock desirable, it can easily be added, as herein disclosed. The power-off lock 68 consists of an electro-magnetic coil 69 suitably supported on brackets 70 straddling the yoke 34 and secured to the ties 22 similarly as the bracket 31. The plunger 71 operable with the armature 72 of the electro-magnetic coil 69 normally to a retracted position with respect to the bar 25, so long as coil 69 is energized -by reason of its electrical connections, indicated at 73 in Fig. 4, with the line circuit 60, is arranged to engage in either one of two holes 74 and 75 provided in the bar 25 under action of a coiled compression spring 76 when a power failure occurs and armature 72 is free to be moved downwardly under action of the spring 76. The yoke 34 has a hole 76 provided therein through which the plunger 71 is free to move to engage in whichever one of the two holes 74 and 75 happens to be in register with the hole 76 at the time of power failure. A pointed end 77 on the plunger 71 reduces the necessity for as close precision in the location of the power-off lock 68 with respect to the bar 25 and makes it more certain that the plunger 71 will be engaged in the hole 74 or 75, as thecase may be, when the power failure occurs, thereby positively locking the switch in oneness 6' whichever position it happens to be set at the time and preventing tampering with it.

It is believed the foregoing description conveys a good understanding of the objects and advantages of my in vention. The appended claims have been drawn to cover all legitimate modifications adaptations.

I claim:

1. In an automatic switch lock for railroads, comprising a throw-bar connected with the switch members to be locked, and spring pressed switch operating mechanism connected with one end thereof and functioning normally to close said switch members, the improvement which consists in the provision of automatically operable switch locking mechanism for selectively locking said switch members in either closed or open position comprising a keeper bar which is a direct extension of the throw-bar and has longitudinally spaced V-notches provided in opposite sides thereof, a pair of opposed elongated latch members each pivoted at one end on a stationary support for releasably locking said keeper bar and each having a Vtooth projecting inwardly from the free end arranged to engage in VBOtCh and said latch members having cam surfaces defined on their outer longitudinal edge portions intermediate their ends in diverging relationship to one another, said keeper bar being reciprocable relative to said support between said latch members, over-center spring means connected to and compressible and expansible between said keeper bar and said latch members tending normally to urge said latch members toward retracted position relative to said keeper bar and to urge the keeper bar toward an extreme position when said means is moved either way past deadcenter by said keeper bar, a yoke raving follower means arranged to engage said cam surfaces to confine the latch members in locking position movable relative to said latch members from their pivoted ends on a line substantially bisecting the angle defined between the cam surfaces on said latch members toward their free ends to force the latch members inwardly toward each other with cam action into locked position with their V-teeth firmly wedgingly engaged in the notches, spring means for re tracting said yoke, and electrical means for operating said yoke in the locking direction controlled by the passage of cars over the switch, whereby the keeper bar is held in locked position during the passage of cars over said switch.

2. In an automatic switch lock for railroads, compris ing a throw-bar connected with the switch members to be locked, and spring pressed switch operating mechanism connected with one end thereof and functioning normally to close said switch members, th improvement which consists in the provision of automatically operable switch locking mechanism for selectively locking said switch members in either closed or open position comprising a keeper bar which is a direct extension of the throw-bar and has longitudinally spaced s -notches provided in one side thereof, an elongated V-toothed latch member pivoted at one end in a stationary support for releasably locking said keeper bar and having a i -tooth projecting inwardly from the free end arranged to engage in either of said V-notches and having a cam suriace defined on the outer longitudinal edge portion intermediate the ends in acute angle relationship to said keeper bar, said keeper bar being reciprocablc relative to said support and latch member, over'center spring means connected to and compressible and expansible between said keeper bar and said latch member tending normally to urge said latch member toward retracted position relative to said keeper bar and to urge the keeper bar toward an extreme position when said means is moved either way past deadcenter by said keeper bar, a yoke having follower means arranged to engage said cam surface to confine the latch member in locking position movable relative to said latch member from its pivoted end toward its free end on a line parallel to said keeper bar to force the latch member inwardly with cam action toward locked position with its V-tooth firmly wedgingly engaged in one of said notches, spring means for retracting said yoke, and electrical means for operating said yoke in the locking direction controlled by the passage of cars over the switch, whereby the keeper bar is held in locked position during the passage of cars over said switch.

3. In a railway switch lock, the combination of a stationary support, a pair of locking dogs pivoted thereon in spaced relation to swing toward one another to locking position, said dogs having V-tecth on their inner sides spaced from the pivoted ends, a keeper bar connected to be movable with the throw-bar of a railway switch and reciprocable between said dogs, said keeper bar having J-notchcs provided in opposite sides thereof in longitually spaced relation positioned for engagement by the V-teeth on said dogs in'locked position when the switch is in open and in closed position, respectively, the V-teeth having wedging engagement in the V-notches when the dogs are in locked position but permitting free movement of the keeper bar relative to the teeth when the dogs are released and retracted, over-center spring means connected to and compressible and expansible between said keeper bar and said dogs tending normally to urge said dogs out wardly toward a diverging relationship in retracted position relative to said keeper bar and to urge the keeper bar toward an extreme position when said means is moved either way past deadcenter by said keeper bar, and means for forcing said dogs inwardly toward locked position.

4. In a railway switch lock, the combination of a stationary support, a locking dog pivoted thereon to swing toward locking position, said dog having a ti-tooth on its inner side spaced from the pivoted end, a keeper bar connected to be movable with the throw-bar of a railway switch and reciprocable relative to said dog, said keeper bar having V-notches provided in one side thereof in longitudinally spaced relation positioned for engagement by the V-tooth on said dog in locked position when the switch is in open and in closed position, respectively, the V-tooth having wedging engagement in the V-notch when the dog is in locked position but permitting free move-- ment of the keeper bar relative to the tooth when the dog is released and retracted, over-center spring means connected to and compressible and expansible between said keeper bar and said dog tending normally to urge said dog outwardly toward retracted position at an acute angle relative to said keeper bar and to urge the keeper bar toward an extreme position when said means is moved either way past dead-center by said keeper bar, and means for rorcing said dog inwardly toward locked. position.

5. In combination, a support, a pair of locking dogs pivoted thereon in spaced relation to swing toward one another to locking position, said dogs having V-teeth on their inner sides spaced from the pivoted ends, a bar reciprocable between said dogs having V-notches provided in opposite sides thereof in longitudinally spaced relation located for engagement by the V-teeth on said dogs in locked position when the bar isin either of two extreme positions, the V-teeth having wedging engagement in the V-notches when the dogs are in locked position but permitting free movement of the bar relative to the teeth when the dogs are released and retracted, an over-center spring means connected to and compressible and expansible between said bar and said dogs tending normally to urge said dogs outwardly toward a diverging relationship in retracted position relative to said bar and to urge the bar toward an extreme position when said over-center means is moved either way past dead center by said bar, a yoke reciprocable on a line parallel to said bar between said dogs carrying rollers riding on the dogs for anti-friction camming thereof inwardly to ward each other to locked position upon movement of the yoke in one direction and release thereof upon move- '7 meat of the yoke in the other direction, and means for reciprocating said yoke.

6. In combination, a support, a locking dog pivoted thereon to swing to locking position, said dog having a V-too-th on the inner side thereof spaced from the pivoted end, a bar reciprocable relative to said dog having V- notches provided in one side thereof in longitudinally spaced relation located for engagement by the V-tooth on said dog in locked position when the bar is in either of two extreme positions, the V-tooth having wedging engagement in the V-notches when the dog is in locked position but permitting free movement of the bar relative to the tooth when the dog is released and retracted, an over-center spring means connected to and compressible and expansible between said bar and said dog tending normally to urge said dog outwardly toward retracted position relative to said bar and to urge the bar toward an extreme position when said over-center means is moved either way past deadcenter by said bar, a yoke reciprocable on a line parallel to said bar and carrying a roller riding on the dog for anti friction camming of the dog inwardly toward the bar to locked position upon movement of the yoke in one direction and release thereof upon movement of the yoke in the other direction, and means for reciprocating said yoke.

7. in combination, a support, a pair of toothed locking dogs pivoted thereon in spaced relation to swing toward one another to locking position, a bar reciprocable between said dogs having notches provided in opposite nected with the dogs to move the dogs to locked position upon movement of the yoke in one direction and for release thereof upon movement of the yoke in the other direction, and means for operating said yoke.

8. In combination, a support, a toothed locking dog piv oted thereon to swing to locking position, a bar reciprocable relative to said dog having notches provided in one side thereof in longitudinally spaced relation located for engagement by a tooth on said dog in locked position,

over-center spring means connected to and compressible and expansible between said bar and said dog tending normally to urge said dog toward retracted position relative to said bar and to urge the bar toward an extreme position when said over-center means is moved either way past deadcenter by said bar, a yoke reciprocable relative to said bar and dog operatively connected with the dog to move the dog to locked position upon movement of the yoke in one direction and for release thereof upon movement of the yoke in the other direction, and means for operating said yoke.

9. In combination, a support, a pair of toothed locking dogs pivoted thereon in spaced relation to swing toward one another to locking position, a bar reciprocable' between said dogs having notches provided in opposite sides thereof in longitudinally spaced relation located for engagement by teeth on said dogs in locked position, compressible and expansible springs disposed between the bar and said dogs, plunger means caging said springs and pivotally connected to said bar and said dogs so as to move the springs over deadcenter in the reciprocation of said bar relative to said dogs, a yoke reciprocable relative to said bar and dogs operatively connected with the dogs to move the dogs to locked position upon movement of the yoke in one direction and for release thereof upon movement of the yoke in the other direction, and means for operating said yoke.

l0. in combination, a support, a toothed locking dog pivoted thereon to swing to locking position, a bar reciprocable relative to said dog having notches provided in one side thereof in longitudinally spaced relation located for engagement by a tooth on -said dog in locked position, compressible and expansible springs disposed between the bar and said dogs, plunger means caging said springs and pivotally connected to said bar and said dogs so as to move the springs over deadcenter in the reciprocation of said bar relative to said dogs, a yoke reciprocable relative to said bar and dog operatively connected with the dog to move the dog to locked position upon movement of the yoke in one direction and for release thereof U301] movement of the yoke in the other direction, and means for operating said yoke.

References (Iited in the file of this patent UNITED STATES PATENTS 908,979 Dufiie Jan. 5, 1909 1,675,176 Jarecki June 26, 1928 2,018,765 Preston et al. Oct, 29, 1935 2,546,454 Kromholz Mar. 27, 1951 FORElGN PATENTS 181,331 Great Britain May 3, 1923 326,133 Italy May 1, 1935 

